The search function uses regular expressions for searching the string in a page.
So '+' means something else(to be precise: "atleast one") in regular expression. To make search() to recognize your '+' as '+' and not something else, you have to escape that character.

I have one more doubt.I am saving the value for eg "C++","Javascript" in a cookie.In the cookie it is stored as "C++","Javascript".But If I retrieve the cookie value using $_COOKIE['ss']; value is retrieved as "C\\ \\","Javascript".

So I can't able to retrieve the cookie value.Anyone suggest me a good solution pls....